Koopa Troopa Beach is the third track of the Mushroom Cup. It takes place on the sandy shores of a mostly rocky island. The way racers drive around the middle of the island is reminiscent of Koopa Beach 2. A large Koopa-shaped rock appears near the starting line. There are several ramps near the middle and end of the course. One leads to a tunnel cutting through the island that acts as an effective shortcut; another is taller than the rest and leads to an Item Box perched on a rock that always contains a Spiny Shell.

Crabs are the main obstacles on this track, and touching them causes a spin-out. Palm trees can also cause spin-outs. The tide can cause trouble if trying to take a certain shortcut near the middle of the course.

Koopa Troopa Beach returns in Mario Kart 7 as the first course of the Banana Cup under the name N64 Koopa Beach. It has gone throuh a complete aesthetic overhaul, but remains largely unchanged gameplay-wise. The only significant difference is that some longer boost pads have been changed into glider pads to take advantage of Mario Kart 7's gliding mechanic, and players can now drive under some submerged areas.